Ordnance calculating apparatus



ZBS'WOQ Nov. 16, 1965 Filed May 25. 1953 SH 1 3s'2189438 C. F- ABT ETAL ORDNANCE CALCULATING APPARATUS &

2 Sheets-Sheet 1 INVENTO'RS.

Clifford F. Abt Richard \4 Arnold Spitalny Miner AT TOR N EV.

Nov. 16, 1965 c. F. ABT ETAL 3,213,438

ORDNANCE CALCULATING APPARATUS Filed May 25, 1953 2 Sheets-Sheet 2 g INVENTOES.

Clifford F. Abr Richard Y. Miner Arnold Spiraln I ATTOR N EY- United States Patent 3,218,438 ORDNANCE CALCULATING APPARATUS Clilford F. Abt, Long Island City, Richard Y. Miner, Port Washington, and Arnold Spitalny, New York, N.Y., as-

signors to American Bosch Arma Corporation, a corporation of New York Filed May 25, 1953, Ser. No. 357,263 7 Claims. (Cl. 23561.5)

The present invention relates to ordnance calculating equipment and has particular reference to computers which indicate the proper course for an attacking vessel when fixed train weapons are employed.

The computer of this invention, using the electromechanical components, solves for the course which the attacking vessel should follow to score a hit on the target vessel from information indicative of the position and motion of the target, the speed of the attacking vessel and the ballistic characteristics of the weapon. The computer also indicates the change in course required to put the vessel on the attacking course, and the time remaining before the missile is to be released or fired.

The solution obtained is valid for either straight course or curved course path of the target, as will be made clear in the following description.

For a more complete understanding of the problem and the method of solution, reference may be had to the accompanying diagrams, in which:

FIG. 1 shows the geometry for the solution when the target is following a straight course,

FIG. 2 illustrates the geometry when the target is following a curved course,

FIG. 3 shows two separate solutions which are possible correct solutions; and

FIG. 4 is a schematic wiring diagram of the computing circuit.

The problem involved, and the geometry used in its solution are shown in FIG. 1. An attacking vessel, or own ship at O, is traveling a course Co at a speed S0 and its observation station X locates a target submarine at E at a relative bearing Br and at a range R from O. The

motion of the target is analyzed by computing apparatus I (not a part of this invention) such as that described in the copending application Serial No. 96,688 filed June 2, 1949, and Serial No. 170,846 filed June 28, 1950, both assigned to the assignee of this invention, and it is thereby established that the target is moving on a course C with a speed S and at a depth Hq below the surface of the water. The computing apparatus also indicates the target angle A, the angle between the path of the target and the line of sight measured clockwise from the bow, and the curvature, Q, of the target track.

The attacking vessel carries a projectile which has an effective (fixed) range Re which is fired from point Y on the attacking vessel in a direction fixed relatively to the attacking vessel, i.e. at an angle Bgrj measured clockwise from the bow. The projectile has a time of flight Tf, after which the projectile hits the water and sinks vertically at a rate Sd. The problem therefore is to maneuver the attacking vessel to a position and course such that the projectile will hit the target if launched at the correct time. The present instrument is capable of solving the problem for a number of different weapons by merely changing the input values of Re, Bgrj, Tf, Sd and the baseline P between X and Y. The circuit shown in FIG- URE 4 is for one weapon only and this weapon may be one which launches a projectile, such as a rocket for example, from a point Y which is located at a distance P forward of the observation point X, both X and Y being on the longitudinal axis of the vessel. The circuit of FIG. 4 is equally valid for depth charge attack, or for ice collision with the bow when appropriate input values are inserted.

The instrument calculates a relative bearing angle cBr which would be observed if the vessel were on the correct course cCo to be able to score a hit, and also indicates the time remaining before the vessel is in the position from which the projectile should be launched to score a hit. Thus, in FIG. 1 the attacking vessel should be following a course such that cBr is equal to Br-jCo where jCo is the required change in course.

In the approach of the attacking vessel along the required course 0C0, the observation point X moves from the initial position through a distance S0(Tud+Tg), where Tud represents the time remaining to fire or until the vessel is in position to fire and Tg is the dead time or the time elapsed between initiation of firing of the projectile and the actual launching of the projectile. The projectile has two components of flight; one component, in the direction of motion of the vessel, is equal in length to SoTf where T is the time of flight of the projectile while the other component is in the direction Bgrj and is equal in length to Re. The projectile enters the Water at G, which is located according to the vectorial sum of SoTf and Re from the point Y and sinks vertically to a depth Hq in the time Td=Hq/Sd. Thus the total time elapsed from the beginning of the approach to the arrival of the weapon at depth Hq is equal to the sum of Tud-l-Tg-i-Tf-l-Td and during this time the target moves from E to G through a distance S(Tud+T g+Tf+T d).

FIGURE 1 shows the geometric relationship of these values and with the aid of FIG. 1 the solution for cBr and Tud can be derived in the folowing manner: Lines GM and 1N are drawn from the extremities of S(Tud+Tg+Tf+Td) and S0(Tud+Tg+Tf) +P, respectively perpendicularly to the initial line of sight, R. Also, line II is drawn perpendicularly to the line GM (extended, if necessary, as in FIG. 1). From the resulting triangles the following equations may be written:

and

Equations 1 and 2 may be rewritten as Equations 3 and 4 respectively:

(S0(Tud+Tg+Tf)+P) cos cBr:RS(Tud l-Tg-i-Tf-i-Td) cos A-Re cos (Bgrj-cBr) (3) and FIGURE 1 shows the geometric solution when the target is travelling on a straight path. If the target is on a circular course such as U for example, the point of impact is at G and the geometry of the solution is changed as shown in FIG. 2.

It is merely necessary to substitute the value of EM for S(Tud+Tg+Tf+Td) cos A in Equation 3 and to substitute the value of GM' for the value of in Equation 4, where GM is perpendicular to R. For this purpose, GB is drawn perpendicularly to the straight path EG, DD is perpendicular to R and GL is perpendicular to DD. Representing the length of GB as jHy and the length of GD as jHx, the following relationships are derived from FIG. 2.

Thus

and

The length of are U is S(Tud+Tg+Tf+Td) and is also equal to ZW, where Z is the radius of curvature of U, and W is the central angle subtended by U. Z, therefore, is equal to S(Tud+Tg+Tf+Td)/W.

From FIG. 2:

' It is possible to arrive at two solutions to the problem as shown in FIG. 3, where one solution for Co+jCo is C01 and the other solution for Co+jCo is C02. The present invention selects the shortest path, i.e. selects C01 as the proper course to follow.

A schematic diagram of the circuit for solving the problem is shown in FIG. 4. It is well known that the successful operation of the motors and electromechanical resolvers requires auxiliary equipment such as amplifiers, damping devices, filters and phase shifters, for example, and to reduce the complexity of the description these units have been omitted from FIG. 4.

A two-phase constant alternating voltage power supply is available, and in FIG. 4 the symbols 5 and are used to represent the two phases. The motors employed in the invention are preferably two phase induction motors wherein the main field winding is energized by the voltage which is in quadrature with the signal voltage applied to the control field windings. Also, the generators which supply damping to certain of the motors are two phase induction generators wherein the main field winding is energized by and the output voltage of the output winding is proportional to the speed of the generator rotor and corresponds in phase to The expression a voltage proportional to a quantity denotes that the amplitude of the voltage is proportional to the magnitude of the quantity and that the phase angle of the voltage is shifted by 180 when the sign of the quantity reverses.

The values of Bgrj, Re, Tg+Tf and 1/Sd for the particular weapon being used are manually inserted into the instrument by displacing the respective shafts 10, 11, 12 and 13 by amounts proportional to these values. Shafts 14, 15, 16, 17, 18 and 19 are displaced angularly according to the respective values of Br, R, A, S, Hq and Q (the curvature of the target track) as indicated by the observing and calculating apparatus previously referred to. Since the values of Br, R, A, S, Hq and Q are con- 4 tinuously changing, the shafts 14, 15, 16, 17, 18 and 19 are preferably controlled by servo mechanisms in the well known manner. Provision for manual displacement should suffice to describe the invention so that the servo systems have been omitted in the interest of simplicity.

Shaft 20 is displaced by an amount proportional to S0, and may be servo-controlled or displaced manually as desired. FIG. 4 shows provision for manual operation of shaft 20.

Shaft 12 drives the movable contact 21 of potentiometer 22, the resistance winding 23 of which is energized by so that the voltage output of potentiometer 22 taken between movable contact 21 and one end of resistance winding 23 is proportional to Tg-i-Tf of the weapon to be fired. Similarly shaft 13 drives the movable contact 24 of potentiometer 25, the resistance winding 26 of which is energized by (1) so that the voltage between movable contact 24 and one end of resistance winding 26 is proportional to l/Sd of the weapon to be fired.

The primary winding 27 of induction potentiometer 28 is energized by the output voltage of potentiometer 25. The secondary or rotor winding 29 of induction potentiometer 28 is driven by shaft 18 so that the voltage induced in secondary winding 29 is proportional in magnitude to the product of l/Sd and Hq or Hq/Sd=Td. The multiplication method of obtaining Td as used and described here is simpler to instrument than a method requiring division of Hq by Sd.

The secondary winding 29 is connected in series with the output terminals of potentiometer 23, the secondary winding 30 of potentiometer 31 and the primary winding 32 of potentiometer 33 so that the voltage energizing primary winding 32 is the algebraic sum of the output voltages of potentiometers 29, 23 and 31. Using the symbol Tx to denote the output voltage of secondary winding 30, the voltage energizing primary winding 32 is therefore proportional in magnitude to The secondary winding 34 of potentiometer 33 is driven by shaft 17 so that the voltage induced in secondary winding 34 is proportional to the product S(Tx+Tg+T f+T d). Secondary winding 34 energizes the primary winding 35 of electromechanical resolver 36 through the closed switch 37. Thiscondition prevails when the target is pursuing a straight course so that shaft 19 is in the zero displacement position and cam 38, driven by shaft 19 opens the switch 38' to deenergize relay winding 39. The deenergized relay winding 39 allows the movable contacts of switches 37 and 40 to be urged to the left by spring 39 thus connecting secondary winding 34 directly to primary winding 35, and at the same time short circuiting the other primary 41 of resolver 36. The rotor windings 42 and 43 of resolver 36 are driven according to A by shaft 16 so that the voltages induced in rotor windings 42 and 43 respectively are proportional to S(Tx+Tg+Tf+Td) sin A and S(Tx +Tg+Tf+Td) cos A.

Shaft 15 drives the secondary or rotor winding 44 of induction potentiometer 45 according to R While the primary or stator winding 44' of potentiometer 55 is energized by so that the output voltage of rotor winding 44 is proportional to R.

Shaft 11 drives the movable contact 46 of potentiometer 47, the resistance winding 48 of which is energized by so that the output voltage of potentiometer 47 taken between one end of resistor 48 and the movable contact 46 is proportional to Re. The output of potentiometer 47 energizes the stator or primary winding 49 of resolver 50, the rotor or secondary windings 51 and 52 of which are driven by shaft 53. Shaft 53 is the output shaft of mechanical differential 54, the displacement of shaft 53 being proportional to the difference between the displacements of the input shafts 10 and 55 of mechanical differential 54. Designating the displacement of shaft 55 for the present as 0, the displacement of shaft 53 is proportional to (Bgrj) and the voltage outputs of rotor windings 51 and 52 are respectively proportional to:

Re cos (Bgrj-O) and Re sin (Bgrj-0) Rotor windings 43, 44 and 51 and stator winding 56 of resolver 57 are connected in series so that the voltage energizing stator winding 56 is proportional to:

Also, rotor windings 42 and 52 and stator winding 58 of resolver 57 are connected in series in a manner such that the voltage energizing stator winding 58 is proportional to:

One rotor or secondary winding 59 of resolver 57 is connected to the left hand stationary contacts 60a, 61a of switches 60 and 61. The cooperating movable contacts 60b, 61b are connected in series with the control winding 63 of motor 64 and with the output winding 65 of generator 66, which provides damping for motor 64. The main field winding 64' of motor 64 is energized by while the main field winding 66' of generator 66 is energized by qb Motor 64 is therefore energized by the difference between the voltage at contacts 60b, 61b and the voltage output of generator 66 so that when the contacts 60b, 61b cooperate with the contacts 60a, 61a motor 64 drives shaft 55 and the rotor winding 59 of resolver 57 until the rotor Winding 59 is in the non-inductive posi tion and the motor 64 is deenergized. In this condition the displacement of shaft 55 is represented by the symbol 0 as previously noted, and the output of the other rotor winding 67 of resolver 57 is designated, for the present as V.

The rotor winding 67 is connected in series with the output of potentiometer 69, taken between movable contact 70 and end tap 71 of resistor 72 and with terminals 68, so that the voltage at terminals 68 is the algebraic difference between the outputs of rotor winding 67 and potentiometer 69. The resistance winding 72 of potentiometer 69 is energized by and the movable contact 70 is displaced along the resistor 72 according to the baseline distance P, as read on dial 70, so that the voltage output of potentiometer 69 is proportional to P whence the voltage at terminals 68 is proportional to V-P.

Terminals 68 are connected in series with the rotor winding 73 of induction potentiometer 74 and with control winding 75 of motor 76 in a manner such that the voltage energizing the control winding 75 is the algebraic difference of the voltage at terminals 68 and the output of rotor winding 73. The stator winding 77 of potentiometer 74 is energized by the sum of the voltage outputs of potentiometers 22 and 31 or by a voltage proportional to (T g|-Tf+Tx) while the rotor winding 73 is displaced according to So by shaft 20 so that the output voltage of rotor winding 73 is proportional to So(Tg+Tf+Tx) and the voltage energizing control winding 75, is proportional to V-PS0(Tg+Tf+Tx). Motor 76 therefore drives shaft 73 and thereby drives the rotor winding 30 of potentiometer 31 until the voltage energizing control winding 75 is zero, and motor 75 stops. In this condition V-PS0(Tg+Tf+Tx), the excitation voltage of control winding 75, is zero so that Thus, in the steady or solution condition the resolver 57 is in a condition where the displacement of the rotor windings 59 and 67 is 0, the output voltage of rotor winding 59 is zero and the output voltage of rotor winding 67 is proportional to S0(Tx+Tg+Tf)-P.

It is well known that when the output voltages of the secondary windings of an electro-mechanical induction resolver are proportional to V and zero, and the displacement of the rotor with respect to the stator is 6 then the resolver primary windings are energized by voltages proportional to V cos 0 and V sin 0. Therefore it can be written that the excitation voltages of stator windings 56 and 58 are proportional to Comparison of the Equations 3 and 4 with Equations 11 and 12 shows that when the instrument reaches a solution or steady state condition the displacement of shaft 55 corresponds to cBr and the displacement of shaft 78 corresponds to Tud.

The solution of cBr at shaft 55 may be transmitted to a remote fire control station by means of self synchronous transmitting and receiving equipment. The rotor winding 79 of self synchronous generator 80 is therefore driven by shaft 55 and is energized by while the stator windings 81 are connected to terminals 82, through switches 83, from whence the position signals are transmitted to the remote station.

Similarly the Tud value may be transmitted by self synchronous apparatus (not shown) if desired, or simply read on dial 78'.

The correction to the course of own ship, jCo, is found by subtracting cBr from Br to obtain BrcBr=Br-Br-| 'C0= 'C0 To this end, Br is introduced at self synchronous transmitter 84' by rotating energized rotor winding 85 by an amount proportional to Br by means of shaft 14. The stator windings 86 of transmitter 84 are connected to the stator windings 87 of self synchronous differential 88, the rotor windings 89 of which are driven by shaft 55 to produce position signals in the rotor windings 89 corresponding to BrBr+jC0. The rotor windings 89 are connected through switches 90 to the stator windings 91 of self synchronous control transformer 92.

The rotor winding 93 of control transformer 92 is driven by shaft 94 of motor 95 the main field winding 95 of which is energized by 5 The output of rotor winding 93 energizes the control winding 96 of motor 95 jointly with the output of output winding 97 of generator 98, the main field winding 98 of which is energized by o and the rotor of which is driven by shaft 94. Motor 95 therefore drives the rotor winding 93 to the non-inductive position and when the motor 95 stops, the displacement of shaft 94, indicated on dial 94' corresponds to jCo. The generator 98 provides a damping voltage, assuring a smooth response of motor 95 to the error signal of rotor winding 93.

When the solution indicates a value of Tad greater than a specified maximum, e.g. T ud-max=300 seconds, the cam 100 on shaft 78 closes switch 101 to energize relay winding 102 from the power supply 103, and a mechanical stop prevents further rotation of shaft 78. Energization of relay winding 102 draws the movable contacts of switches 104, 105 into cooperation with the corresponding left hand stationary contacts against the action of spring 106. Closure of switch 104 connects a resistance 107 across the control Winding 75 to protect the control winding 75 from being overloaded, while closure of switch 105 causes energization of the relay winding 108. In this instance, the energization of relay winding 108 is not effective in changing the operation of the instrument since the movable contacts of switches 109 and 110 actuated to the left thereby against the action of spring 111, are connected to open circuits. With the instrument in this condition the motor 64 continues to present a solution for cBr consistent with a Tud value of T udmax. When the input values change sufliciently to decrease the Tud solution below T udmax, switch 101 opens to deenergize relay winding 102 and put the instrument in normal operating condition.

For some weapons, the observation station is forward of the launching point Y so that the baseline P is a negative quantity, as in the case of depth charge racks lo cated at the stern of the attacking vessel for example. Therefore, the quantity S(Tg+Tf+Tud) +P may become negative as the value of Tud approaches zero, i.e. near the end of the attacking run. When the quantity S0( T g+ Tf+ Tud +P reverses, the null signal from rotor winding 59 of resolver 57 also reverses, as seen from the Equations 3 and 4, and the motor 64 slews away from the correct solution. Although the solution breaks down in this situation, provision is made for the computer to continue to display correct values of Tad, jCo and cBr as hereinafter described.

It will be seen that when the function is equal to zero the observation point, X, is at the point where the weapon, Y, will be when the projectile launched by the weapon strikes the water. This condition occurs near the end of the approach and it is assumed therefore that the attacking vessel 0 is already on the correct course. When the vessel 0 is on the correct course, Tud decreases at a constant rate of one second per second of chronological time, jCo is zero and cBr is equal to Br. Thus, an alternative solution wherein jC0=O, cBr=Br and Tud decreases at a constant rate of one second per second is displayed by the computer whenever the quantity So(Tud-|-Tg+Tf) +P is less than an arbitrary value K.

The movable contact 112 of potentiometer 113 is displaced along the resistor winding 114 according to K by turning knob and dial 115 so that the output of potentiometer 113 between end tap 116 and movable contact 112 is proportional in magnitude to K. The K output of potentiometer 113 is matched against the output of the rotor winding 67 of resolver 57 which has been shown to be proportional to So(Tud+Tg+Tf)I-P and the difference voltage is applied to the polarized relay winding 117. When Tud is large, the switches 118 and 119, which are operated by polarized relay winding 117 are open as shown in FIG. 4. When Tad decreases so that S0(Tml+Tg+Tf) +P is less than K, polarized winding 117 is energized by a reverse polarity and switches 118 and 119 are closed. Closure of switch 118 causes energization of relay winding 120 from power supply 103 through series connected switches 118 and 109.

Energization of relay winding 120 draws the armature bar 120' to the left against the action of spring 121, thereby operating the movable contacts of switches 83, 90, 122, 123, 124, 125 and 126 to the left.

Switch 90 connects an electrical-zero signal from transformer winding 127 to the control transformer 92, so that shaft 94 is driven to the zero position by motor 95 and dial 94' displays a zero reading for jCo.

Switch 83 connects the stator windings 86 of transmitter 84 directly to terminals 82 so that the position signals at terminals 82 correspond to Br.

Switch 123 opens the connections between the main field winding 76' of motor 76 and o so that motor 76 is deenergized, while switch 122 energizes the electromagnetic clutch 128 from power supply 103, allowing the constantly energized, constant speed synchronous motor 129 to drive shaft 78 at a constant rate corresponding to a decrease in Tud of one second per second.

Switch 124 supplies an alternate path for the energization of relay winding 120 through switch 109 so that relay winding 120 holds itself closed by means of switch 124.

Switches 125 and 126 open but are not effective in changing the operation of the computer in this instance.

When Tud reaches a value of 2 (minus two) seconds cam causes switch 101 to close, thereby causing energization of relay winding 102 and the consequent energization of relay winding 108 as previously described when Tud=Tudmax. Opening of switch 109 by the relay winding 108, causes relay winding 120 to be deenergized so that the instrument displays the computed solution, While closure of switch 110 holds relay winding 108 energized through switch 119.

As soon as S0(Tud+Tg-|-Tf)-|P rises above the K value (during a new problem), relay winding 117 causes actuation of switches 118, 119 to the normal position (as in FIG. 4) to denergize relay winding 108 and return control of relay winding 120 to switch 118.

As stated in connection with FIG. 3, there are always two possible solutions for Tud and jCo. When target speed S is greater than own ship speed So one solution gives a course heading away from the target (C02 in FIG. 3) so that own ship is in the attacking position when the target catches up to own ship. The other solution is the desirable one and is a course heading toward the target for quick interception. At long range, the solution for quickest interception is the one with the value of cBr closest to zero degrees. The computer selects this solution and then follows the problem through all quadrants without interference. However, it will not change the solution if the attacking vessel is already following a computed course (jC0=0) when S becomes greater than $0.

The resistance windings 131' of resistance potentiometers 130 and 131 respectively are energized by 42 while the respective movable contacts 132 and 133 are driven by shafts 17 and 20. The output of potentiometer 130 is therefore proportional to S while the output of potentiometer 131 is proportional to S0. Movable contacts 132, 133 are connected in series with polarized relay winding 134 in a manner such that when S0 is greater than S the switches 135, 136, actuated by relay 134, are as shown in FIG. 4, while reversal of the energization of relay winding 134 (when S is greater than So) causes the switches 135, 136 to be actuated to the position opposite that shown in FIG. 3, i.e. the switches 135, 136 are closed.

When own ship is on the attacking course so that jCo is zero, cam 99 driven by shaft 94 is in position such that switch 137 operated thereby is open, as actuator bar 137' is received by the notch in cam 99, and the computer continues in its normal solution operation,

If, however, own ship is not on course, so that switch 137 is closed, closure of switch 136 energizes relay winding 138 through switches 139 and 126 to operate the movable contacts of switches 60, 61, 140 and 141 to the right to effect the following:

Switches 60 and 61 disconnect the motor 64 and generator 65 from the rotor winding 59 of resolver 57 and connects the motor-generator 6565 to two of the stator windings 81 of self synchronous generator 80, the voltage across which is proportional to the sine of the displacement of shaft 55. Motor 64 therefore drives the rotor winding 79 until the voltage energizing motor 64 is zero and shaft 55 is in the zero position. Switch 140 holds relay winding 138 energized although switch 137 may open, While closure of switch 141 allows relay winding 142 to be energized by power supply 103 when shaft 55 reaches the zero displacement position and cam 143 driven thereby closes switch 144.

When cBr reaches zero relay winding 142 is energized and the movable contacts of switches 139 and 145 are thereby urged to the right against the action of spring 146. Actuation of switch 139 opens the circuit to relay winding 138 so that the cBr servo motor is again controlled by resolver 57 and computer operates normally to solve for the cBr nearest zero.

Relay 142 remains energized to maintain relay winding 138 deenergized until the run is completed and relay 142 is opened by switch 125 which is operated when relay winding 120 is energized after Tud reaches 2, or until S is greater than S so that switch 135 is opened by relay winding 134.

The instrument also solves for the required values cBr, '00 and Tud when the target vessel is travelling on a curved course such that shown by the are U in FIG. 2, according to the Equations 7 and 8. In order to solve the curved course equations it is seen that the excitation voltages of the stator windings 35 and 41 of resolver 36 should be proportional, respectively to This is accomplished in the following manner: The S(Tud+Tg+Tf-|-Td) output of rotor winding 34 energizes the stator winding 150 of potentiometer 151, the rotor winding 152 of which is displaced by shaft 19 according to Q. The output voltage of rotor winding 152 is proportional to QS(Tud+Tg+Tf+Td) which is equal to W, since Q by definition is equal to l/Z and as shown earlier, or W=S(Tud+Tg+Tf+Td)/Z.

The W signal voltage is changed into a proportional shaft displacement by motor 153 in the usual manner. Motor 153 drives the shaft 154 and thereby displaces rotor winding 155 of potentiometer 156, the stator winding 157 of which is energized by The rotor winding 152 is connected in series with rotor winding 155 and the difference voltage energizes the control field winding 158 of motor 153, the main field winding 159 of which is energized by so that motor 153 drives shaft 154 until the voltage output of rotor winding 155 matches the output of rotor winding 152 and the motor 153 is decnergized. In this condition, the displacement of shaft 154 is proportional to W. Shaft 154 drives the input shafts of cam units 160 and 161, the outputs of which displace the rotor windings 162 and 163 respectively of the respective potentiometers 164 and 165 proportionally to 1(sin W/W) and fi Alternatively, resolvers may be used in place of the potentiometers 164, 165. This replacement requires an appropriate change in each of cams 160, 161 whereby the rotors of the resolvers are displaced according to the angle whose sine or cosine is 1oos W W sin W W Then the resolver outputs are proportional to jHx and jHy.

When the target is on a curved course, Q is not zero so that cam 38 closes switch 38' to thereby energize the relay winding 39 so that movable contacts of switches 37 and 40 are urged to the right against the action of spring 39. Actuation of the movable contact of switch 37 to the right connects rotor winding 162 in series with rotor winding 34 and stator winding 35 so that the voltage energizing stator winding 35 is the algebraic difference between the outputs of rotor windings 34 and 162 and is proportional to:

Actuation of the movable contact of switch 40 to the right connects the output of rotor winding 163 to the stator winding 41 which is therefore energized by a voltage proportional to jHy.

Then the output voltages of rotor windings 43 and 42 are respectively proportional to and the instrument will present a solution according to these values, which is the curved course solution.

We claim:

1. In ordnance calculating equipment for indicating the proper course for an attacking vessel when fixed train weapons are employed, means for resolving a first signal representing the effective range of the projectile into second and third signals respectively representing rectangular coordinates in and across the initial line of sight, means for subtracting one of said second and third signals from a fourth signal representing initial range, means for modifying said second and third signals in accordance with the motion of the target and a time value including time remaining to fire, second resolver means energized by said modified signals, motive means controlled by one output of said second resolver means and driving said second resolver means, means for comparing the other output of said second resolver means with a value including the time remaining to fire, motive means energized by the output of said comparing means and means adjusted by said motive means to produce the value of time remaining to fire.

2. In ordnance calculating equipment for indicating the proper course for an attacking vessel when fixed train weapons are employed, means for resolving a first signal representing the effective range of the projectile into second and third signals respectively representing rectangular coordinates in and across the initial line of sight, means for subtracting one of said second and third signals from a fourth signal representing the initial range, means for modifying said second and third signals in accordance with the motion of the target and a time value including time remaining to fire, second resolver means energized by said modified signals, said second resolver being adapted to adjust said first resolver, motive means controlled by one output of said second resolver means and driving said second resolver means, means for comparing the other output of said second resolver means with a value including the time remaining to fire, motive means energized by the output of said comparing means and means adjusted by said motive means to produce the value of time remaining to fire.

3. In ordnance calculating equipment for indicating the proper course for an attacking vessel when fixed train weapons are employed, first resolver means for resolving a first signal representing the eifective range of the projectile into second and third signals respectively representing rectangular coordinates, means for subtracting one of said second and third signals from a fourth signal representing the initial range, means for modifying said second and third signals of said first resolver in accordance with the course of the target and a time value including time remaining to fire, second resolver means energized by said modified signals, motive means controlled by one output of said second resolver means and driving said second resolver means, means for comparing the other output of said second resolver means with a value including the time remaining to fire, motive means energized by the output of said comparing means and means adjusted by said motive means to produce the value of the time remaining to fire.

4, In ordnance calculating equipment for indicating the proper course for an attacking vessel when fixed train weapons are employed, first resolver means for resolving a first signal representing the effective range of the projectile into second and third signals respectively representing rectangular coordinates, means for subtracting one of said second and third signals from a fourth signal representing the initial range, means for modifying said second and third signals of said first resolver in accordance with the course of the target and a time value including time remaining to fire, second resolver means energized by said modified signals, said second resolver means being adapted to adjust said first resolver, motive means controlled by one output of said second resolver means and driving said second resolver means, means for comparing the other output of said second resolver means with a value includ ing the time remaining to fire, motive means energized by the output of said comparing means and means adjusted by said motive means to produce the value of the time remaining to fire.

5. In a computer for ordnance calculating equipment, means for resolving a first signal representing the effective range of the projectile into second and third signals representing rectangular coordinates in and across the initial line of sight, means for subtracting one of said second and third signals from a fourth signal representing the initial range, means for modifying said second and third signals in accordance with the motion of the target and a time value including time remaining to fire, second resolver means energized by said modified signals, motive means controlled by one output of said second resolver means and driving said second resolver means, means for comparing the other output of said second resolver means with a value including the time remaining to fire, motive means energized by the output of said comparing means and means adjusted by said motive means to produce the value of time remaining to fire.

6. In a computer for ordnance calculating equipment, means for resolving a first signal representing the eifective range of the projectile into second and third signals representing rectangular coordinates in and across the initial line of sight, means for subtracting one of said second and third signals from a fourth signal representing the initial range, means for modifying said second and third signals in accordance with the motion of the target and a time value including time remaining to fire, second resolver means energized by said modified signals, said second resolver being adapted to adjust said first resolver, motive means controlled by one output of said second resolver means and driving said second resolver means, means for comparing the other output of said second resolver means with a value including the time remaining to fire, motive means energized by the output of said comparing means and means adjusted by said motive means to produce the value of time remaining to fire.

7. In a computer for ordnance calculating equipment, first resolver means for resolving a first signal representing the effective range of the projectile into second and third signals representing rectangular coordinates, means for subtracting one of said second and third signals from a fourth signal representing the initial range, means for modifying said second and third signals of said first resolver in accordance with the course of the target and a time value including time remaining to fire, second resolver means energized by said modifiedsignals, motive means controlled by one output of said second resolver means and driving said second resolver means, means for comparing the other output of said second resolver means with a value including the time remaining to fire, motive means energized by the output of said comparing means and means adjusted by said motive means to produce the value of the time remaining to fire.

References Cited by the Examiner UNITED STATES PATENTS 1,985,266 12/1934 Smith 235-615 2,066,949 1/1937 Ruiz 235-61 2,433,843 1/1948 Hammond 235-615 MALCOLM A. MORRISON, Primary Examiner.

CHESTER L. JUSTUS, NORMAN H. EVANS, IRVING L. SRAGOW, Examiners. 

1. IN ORDNANCE CALCULATING EQUIPMENT FOR INDICATING THE PROPER COURSE FOR AN ATTACKING VESSEL WHEN FIXED TRAIN WEAPONS ARE EMPLOYED, MEANS FOR RESOLVING A FIRST SIGNAL REPRESENTING THE EFFECTIVE RANGE OF THE PROJECTILE INTO SECOND AND THIRD SIGNALS RESPECTIVELY REPRESENTING RECTANGULAR COORDINATES IN AND ACROSS THE INITIAL LINE OF SIGHT, MEANS FOR SUBTRACTING ONE OF SAID SECOND AND THIRD SIGNALS FROM A FOURTH SIGNAL REPRESENTING INITIAL RANGE, MEANS FOR MODIFYING SAID SECOND AND THIRD SIGNALS IN ACCORDANCE WITH THE MOTION OF THE TARGET AND A SIGNAL VALUE INCLUDING TIME REMAINING TO FIRE, SECOND RESOLVER MEANS ENERGIZED BY SAID MODIFIED SIGNALS, MOTIVE MEANS CONTROLLED BY ONE OUTPUT OF SAID SECOND RESOLVER MEANS AND DRIVING SAID SECOND RESOLVER MEANS, MEANS FOR COMPARING THE OTHER OUTPUT OF SAID SECOND RESOLVER MEANS WITH A VALUE INCLUDING THE TIME REMAINING TO FIRE, MOTIVE MEANS ENERGIZED BY THE OUTPUT OF SAID COMPARING MEANS AND MEANS ADJUSTED BY SAID MOTIVE MEANS TO PRODUCE THE VALUE OF TIME REMAINING TO FIRE. 